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LT40 strange out of square problem.

Started by Dave Shepard, June 15, 2014, 02:13:20 PM

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isawlogs

I had a similar issue with my mill. It was the out side roller (drive side)  that had an issue. the mounting screws had loosened a tiny bit and would let the roller up a tiny bit, wich caused the out of square issue. I have replaced all the set screws and locking nutsand all is good now.
A man does not always grow wise as he grows old , but he always grows old as he grows wise .

   Marcel

AnthonyW

There is a 5-cut method to square a table saw. The same can be used here to determine how much the mill is off from square.

In reality the first four cuts are the most important. If it is out of square at that point it will remain out of square, if everything on the mill is tight. If there is something loose or flexing, the out of square will get progressively worse. After you make the first two cuts, and the second is using the back stops only, are they square?

I was lucky. I was cutting boards that came off out of square. But they were all out of square by the same amount. A performing the complete alignment, the boards are and cants are nearly perfectly square.

If you were to take a 'scrap' log and filtch the whole thing (no turning) does the problem get progressively worse by the time you get to the bottom? Or do all the boards come out the same dimensions?

'97 Wood-Mizer LT25 All Manual with 15HP Kohler

kelLOGg

Could the band be rising or diving? When I experience cuts of non-uniform thickness I will back up the band to the cut it has just exited to see if the back of the band lines up with the kerf line. When the band starts to get dull I willl see a mis-alignment, usually the band has risen leaving the cant a little thicker on the moveable roller side (entry). This will give me a non-square cant. Just a suggestion based on my experience.
Bob
Cook's MP-32, 20HP, 20' (modified w/ power feed, up/down, loader/turner)
DH kiln, CatClaw setter and sharpener, tandem trailer, log arch, tractor, thumb tacks

bandmiller2

Only thing I can think of now is a band problem Dave,  you must have tried a different and/or new band. Frank C.
A man armed with common sense is packing a big piece

Dave Shepard

Quote from: Magicman on June 15, 2014, 10:28:34 PM
Dave, my remarks only applied to my situation and I have never sawed a 30' log.  I did not pick up on the fact that you are sawing 30' timbers.  Your market is completely different from mine and obviously a different set of rules apply.

Since you have a bed extension, have you verified that it has not settled or is maybe twisted.

Obviously there is something that you are missing somewhere in your measurements or alignments or else you would not be having a problem.  Maybe back to square one.   :-\

I have checked the BX to the main bed frame, and it is in "wind" (old woodworkers saying). I still have the problem working on short timbers, so I don't think the BX is a problem. I am going to saw a short log on the BX, to try and eliminate any issues with clamping or misalignment on the main frame.

The problem is I don't know if it's a measurement or alignment problem, or some sort of weird bearing issue. Short of replacing all the bearings, I don't know where to look. All measurements are according to the book right now.

Quote from: 5quarter on June 15, 2014, 11:38:31 PM
Dave...I know you said that clamping is not the problem, but I think it is. It explains all the facets of your trouble. if your backstops are square to the rails, and if the cant is laying flat on all the rails and your blade is running parallel to the rails through the entire cut, you cannot be out of square. When you clamp your cant, it appears to lay flat on the rails, yes? But when you engage the blade and begin sawing, you are putting a lot of lateral force on the cant...esp. with that big cat engine. and the faster you saw, the greater that lateral force becomes. something has changed in the clamping system that it cannot hold some pieces flat to the rails while in the cut. What has changed I have no idea. perhaps the angle of the cleat, perhaps something is bent slightly. But that's definitely a gremlin you need to shoot dead, and quick.

I also agree with Peter...after I open the first face, I rotate 90°. That second cut is the money cut.  ;)

I don't know what could have changed with the clamping system. It's clamping, hard if I want it to, the same as it always has. I've run this mill since new, so it's not a matter of me not knowing the power of the engine.

Quote from: AnthonyW on June 16, 2014, 05:56:38 AM
There is a 5-cut method to square a table saw. The same can be used here to determine how much the mill is off from square.

In reality the first four cuts are the most important. If it is out of square at that point it will remain out of square, if everything on the mill is tight. If there is something loose or flexing, the out of square will get progressively worse. After you make the first two cuts, and the second is using the back stops only, are they square?

I was lucky. I was cutting boards that came off out of square. But they were all out of square by the same amount. A performing the complete alignment, the boards are and cants are nearly perfectly square.

If you were to take a 'scrap' log and filtch the whole thing (no turning) does the problem get progressively worse by the time you get to the bottom? Or do all the boards come out the same dimensions?



I square to the bed at every turn. If the vertical face is not square to the bed, I jack it up with the two plane clamp until it is. I never rely solely on the backstops for a timber cut. Boards, yes, it doesn't matter if the edge of a board is off 1/128" over an inch. :D

Quote from: kelLOGg on June 16, 2014, 06:01:29 AM
Could the band be rising or diving? When I experience cuts of non-uniform thickness I will back up the band to the cut it has just exited to see if the back of the band lines up with the kerf line. When the band starts to get dull I willl see a mis-alignment, usually the band has risen leaving the cant a little thicker on the moveable roller side (entry). This will give me a non-square cant. Just a suggestion based on my experience.
Bob

Quote from: bandmiller2 on June 16, 2014, 06:53:30 AM
Only thing I can think of now is a band problem Dave,  you must have tried a different and/or new band. Frank C.

This has been going on over the course of about 25 bands. One new box and 15 ReSharps. My cuts are very good, unless I push the band too far, which I did once and got some waves.

I appreciate all the input. I know it sounds like I'm disputing all of the suggestions, but I guess that is why I'm so stumped. I've tried all of the usual suspects, and don't know what else to try. I'll put in a call to WM when I get a chance and see what they say. They will surely have run into just about any problem there is with an LT40. Thanks.
Wood-Mizer LT40HDD51-WR Wireless, Kubota L48, Honda Rincon 650, TJ208 G-S, and a 60"LogRite!

OneWithWood

Dave, when you clamp do you clamp as low on the cant as possible?
I had a similar problem when I would clamp about half the height of the cant.  Lowered the clamp to within a few inches of the bed and things improved.
One With Wood
LT40HDG25, Woodmizer DH4000 Kiln

Jim_Rogers

You said it was 5" tall on the rail side and 5 1/4" on the clamp side.

This tells me that the cant is thicker on the clamp side. Which means to me that at one "rolling" it was not up tight to the log uprights/back rests whatever you call them.

For sake of clarity we'll call the bed rails the bottom or the table, the two moving pieces that the log is clamped against the log rests or log uprights.

When I was taught how to saw a log they told me to always put these log rest/uprights all the way up every time. 1) so you don't push your log off the table/bed rails and 2) to make sure your vertical face is flush up against them, every time.

If you cut two opposite faces first then you're right they should be parallel. When you do that check by measuring the two sides of the log. If both sides of an 8" cant are 8" then the sides are truly parallel. If they are not then it's a mill alignment problem. You'll need to adjust something to take out the "gain" of the thick side.

Now, once you have the two sides parallel then you should be able to roll one face up against the log back rest/uprights, and then trim off one of the other two faces. This is when you have to check to make sure that your corner is 90° if it is not after one or two cuts taking off boards or planks then you need to tip your cant a bit more, buy pushing up on it with the log turner while it's being held tight with the clamp. If it is taller on the clamp side, which is what you're saying it is.

After that side is done and it truly square (90°) to one of the parallel faces then the fourth face should come out true.

Lots of times I don't cut the last board off the first face until I come all the way around the cant and back to the beginning again. That way I have one face that I can use to true up the cant.

Sighting the cant to make sure that there is no light between the cant and the log rest/uprights is good from the end of the mill, but sometimes you have to actually walk down there to the log rest/upright and look at it and see if there is a small gap at the top. Sometime you need to push the cant a little to close up this gap.

When I check my log rest/uprights I use two pieces of 1" square tubing 4' long across the bed rails/table. And I set my framing square on them, not on a board or plank made out of wood.
Steel checking steel is the best.

Jim Rogers
Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

barbender

I had a bad bearing in the idler sprockets in the lift system once that caused some inconsistencies, I suspect I have another as my head has been "jumpy". Also, what do your mast slide pads look like. I agree, I think you have a bearing problem somewhere.
Too many irons in the fire

drobertson

I have seen it before, for me it has been cam followers, as good as they seemed, just did not hold through the log.  Bed extensions would be a place to look as well.  jacks, and foundation too.  trusting you have it aligned, a head scratcher, blades have done funny things, alignment, and bearings has to be there in the picture.
only have a few chain saws I'm not suppose to use, but will at times, one dog Dolly, pretty good dog, just not sure what for yet,  working on getting the gardening back in order, and kinda thinking on maybe a small bbq bizz,  thinking about it,

bandmiller2

Dave, you know as much or more than any of us here no wonder its got you upset. I would put a level on the saw head and slowly run it to the other end wile watching the bubble. I think you'll see the outside of the head dip slightly, could be bearings or track wear. Frank C.
A man armed with common sense is packing a big piece

Dave Shepard

I talked to Barry at WM today. He didn't have any rare incidents of misalignment to share. I think my next move is to take the track roller bearings off and inspect or replace them. Every other thing has been checked.
Wood-Mizer LT40HDD51-WR Wireless, Kubota L48, Honda Rincon 650, TJ208 G-S, and a 60"LogRite!

derhntr

Dave,
I went through the same as you. Could not get it figured out, every thing looked good. When I had the mill service we found the cam follower bearings on the bottom of the rail were loose. When tightened to specs cant were square again
2006 Woodmizer LT40HDG28 with command control (I hate walking in sawdust)
US Army National Guard (RET) SFC

MReinemann

I'll get out of square on my lt35hd if I over clamp.  Maybe the stops need to be adjusted.  Mine will flex slightly if I apply to much pressure with the clamp.  Sounds like it's not over clamping though after reading through the posts.
-Matt

Dave Shepard

I talked to Jeremy at Hannibal WM a few weeks ago, and he suggested taking the BX off and moving to better ground. The mil was on compacted gravel, with about 4" of smooth 3/4" stone under it. I didn't think it would make much difference, as I had leveled the mill a couple of times with string lines and level since it was put in that location this spring. Well, I've only cut three timbers since moving it, but they have all been square. So, somewhere on the mill something wasn't being supported when the weight of the head and or log was being applied to it. I did do some really big logs on there about the time that the trouble started, but my string line and level checks didn't reveal any problems. I've got a bunch of short sawing coming up, so we'll see how it does. If that's all it was, then I've got to come up with some concrete before I hook up the BX again. The 10"x10" I cut a few minutes ago was absolutely perfect. :)
Wood-Mizer LT40HDD51-WR Wireless, Kubota L48, Honda Rincon 650, TJ208 G-S, and a 60"LogRite!

drobertson

Dave, I have sawn a pile with jacks not solid, and have never seen this,, this said, it is very possible for sure, it has always been the cam followers and or the moveable blade guide arm adjustments. But with this said, things are sometimes weird with logs and clamping, so it could have been a fluke?
only have a few chain saws I'm not suppose to use, but will at times, one dog Dolly, pretty good dog, just not sure what for yet,  working on getting the gardening back in order, and kinda thinking on maybe a small bbq bizz,  thinking about it,

Jim_Rogers

I'm finding that really hard to believe. I've set up my mill down hill to the end, leaning to the side and up on blocks, and never had a problem with these positions making timbers out of square.

The frame can be "stress" bent, I know because the frost heaved mine more than once. But once you release the frozen down outrigger pads the mill pops back to being level and true, with no permanent damage.

If the location of your mill has caused your timbers to be out of square something is very wrong.

Sawing with a bed extension that is not completely in line with the mill can cause thick and thin timbers. Don't ask me how I know. But never were they out of square, because of the bed extension.

I don't know it just doesn't sound right to me.

Jim Rogers

Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

Dave Shepard

I think the issue was that the mill had settled unevenly on some of the jacks, and the bed extension was still in it's original location. I am accepting it as the solution for now, as all the other options have been addressed. All portions of the alignment were perfect. All bearings were functioning flawlessly. The only thing left was improper support. The only change I made was to unhook the BX and move the mill over a few feet and put the legs down on very well compacted gravel. Voila! Cutting square again.
Wood-Mizer LT40HDD51-WR Wireless, Kubota L48, Honda Rincon 650, TJ208 G-S, and a 60"LogRite!

Peter Drouin

That's why I have mine on 6" of concrete.


 

What I get is drift of the mill from logs hitting the loader arms :D :D


  

 
See how far the chain is from the mill.
The BX is bolted to the floor, But the mill slides sideways :D :D
There is a piece of steel I'm supposed to put on the other side of the mill . But then I have to take a leg off and reset, So I don't.  :D
A&P saw Mill LLC.
45' of Wood Mizer, cutting since 1987.
License NH softwood grader.

Dave Shepard

When you get your new LT70WideHead with the electric motor, don't forget to order the stationary legs. It will never move then. Unless you ram it with John in high gear. :D

The mill was first setup on concrete. I hope it will be again soon. This slab was 20'x104'.  ;D



 
Wood-Mizer LT40HDD51-WR Wireless, Kubota L48, Honda Rincon 650, TJ208 G-S, and a 60"LogRite!

ladylake


Any mill made will flex and twist if not supported good by jacks or good blocking if stationary resulting in all sorts of problems.  There was just a thread of a TK mill cutting uneven cants which turned out to be too much jack support in the middle.  Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

bandmiller2

Seems with all mill problems its something simple, we all seem to start at the most complex and work back to the simple fix. Glad you found it Dave. Frank C.
A man armed with common sense is packing a big piece

Klicker

Have you checked your clamp. I had a problem once and  my clamp was lifting the can't about 3/8 of an inch when I clamped it tight  I had bent something and it took a while to figure it out. Rod
2006 LT 40 HD

backwoods sawyer

Quote from: Klicker on July 29, 2014, 04:12:47 PM
I had a problem once and my clamp was lifting the can't about 3/8 of an inch when I clamped it tight  I had bent something and it took a while to figure it out. Rod
When I got my mill it was doing the same thing, what I found was the socket the pivot arm sits in was warn so that when clamping the bottom of the cant would catch the 1/2" stops and rock up to meet the stop. Added a thick washer to bring the dogs out flush with the stops. 
If you see the out of sqaure issue again check that the dogs are flush with the stops and that the two adjustable stops match the fixed stops.
Nothing more frustrating then a mill not cutting square.
Backwoods Custom Milling Inc.
100% portable. . Oregons largest portable sawmill service, serving all of Oregon, from our Backwoods to yours..sawing since 1991

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